Patient Education Blog

Pradaxa – Interruption for Colonoscopy, Dental Work, Surgery, etc.

When to stop the drug – General comments

If you are on Pradaxa® (Dabigatran) you may need interruption of therapy for dental work, a medical procedure such as colonoscopy, or minor or major surgical procedure. As to when exactly to take the last dose of Pradaxa® before the procedure depends on (a) how big a procedure is planned and how much bleeding is expected to occur with it, and (b) whether a person is at high or low risk for a blood clot if he/she is off “blood thinners” for a few days.

It is important what your kidney function is

The way our body gets rid of Pradaxa® is by excreting it through the kidney into the urine: about 80 % of the drug is excreted unchanged via the kidney. The remainder is excreted via the bile into the stool. In patients with impaired renal function (kidney disease) the drug stays longer in the body. Impaired renal function is assessed by a blood test called serum creatinine. An elevated level indicates impaired kidney function.

How quickly is Pradaxa out of the blood system if you stop it?

In most patients with normal kidney function, Pradaxa®’s blood thinning effect is mostly gone within 1-2 days after the last dose has been taken. This is because the drug is relatively quickly excreted in the kidney. In medical-biochemical terms this is expressed as “half-life” (see table). In the person with normal renal function, half of the Pradaxa® is gone within 13 hours (i.e. the half-life is 13 hours). Another 13 hours later another half of the remaining drug is gone (i.e. a total of 75 % of the drug is now gone), and so on. Typically, after 3 half-lives most of the drug (87.5 %) is gone. Most surgeries with a normal (standard risk) of bleeding can be safely done when the majority of drug is gone. For people with normal renal function that is ca. 24 hours after the last dose has been taken (see table).

However, because the majority of Pradaxa® is excreted in the kidney, the drug will be excreted more slowly in people with impaired kidney function (renal disease). Thus, Pradaxa® needs to be discontinued earlier before surgeries, such as 2 or more days before surgery (see table). If surgeries with a high risk of bleeding are planned, one will want all the drug to be out of the body. Depending on the renal function, the last dose of Pradaxa® would have to be 2 or more days before the surgery (see table below).

Table. Guide to the discontinuation of Pradaxa® before procedures or surgeries (adapted from reference 2)

Many dental procedures can be done on full doses of “blood thinners” [ref 1]. Detailed recommendations exist as to which dental procedures can be done on full dose “blood thinners” (teeth cleaning, root canal, one or two teeth extractions), and for which the level of “blood thinners” needs to be reduced [ref 1 and discussion here]. A similar approach can likely be taken in people on Pradaxa®. However, it is also an easy option to not take the evening dose of Pradaxa® on the day before the procedure and not to take the morning dose on the day of the dental procedure, then restart in the evening of the day of the procedure. However, individualized treatment decisions need to be given.

Colonoscopies and EGDs (=upper endoscopy)

Colonoscopies and EGDs can typically safely be done on full-dose “blood thinners”, but since the gastroenterologist may want to take a biopsy or remove a polyp, one typically wants the patient off “blood thinners”. Again, the kidney function needs to be taken into consideration as to when to take the last dose of Pradaxa® – the table above gives guidance. The person with normal kidney function may not want to take Pradaxa® one day prior to surgery, nor in the morning of the day of the procedure (i.e. will have taken the last dose of Pradaxa® more than 36 hours before the colonoscopy or EGD).

Surgery, minor or major

When to take the last dose before minor or major surgery, again, depends on the degree of expected bleeding with the surgery. The table above gives guidance.

When to restart Pradaxa® after surgery

Pradaxa® quickly “thins” the blood after oral intake: its maximum effect is reached within 2-3 hours of taking it! Therefore, if you are at significant risk for bleeding after a procedure or surgery, the re-start of Pradaxa® may have to be delayed by a few days. Again, individualized decisions need to be made, depending on a person’s risk for bleeding and clotting.

I HAVE BEEN ON PRADAXA 110 MG BID FOR 4 MONTH AS PRE OP BLOOD THINNER. I HAD MY PRE OP TESTS AND CHECK UPS PREPARATIONS COMPLETED TODAY FOR OPERATION ON MONDAY AUG.22/2011. IN THE INSTRUCTION I RECEIVED WITH MY MEDICATION THERE IS NO MENTIONED WHEN TO STOP TAKING PRADAX PRE OPERATION. THE DOCTOR WHO DID THE TESTING SAID HE IS NOT FAMILIAR WITH PRADAXA AS IT IS NEW ON THE MARKET. I HAVE BEGGED THEM TO PROCEED WITH OPERATION ON MONDAY. TODAY IS THURSDAY; I HAVE TAKEN MY MORNING DOSE, BUT WILL STOP NOW UNTIL AFTER OPERATION. IS THIS SUFFICIANT TIME? I AM HAVING TOTAL KNEE REPLECEMENT. PLEASE LET ME KNOW.

Clot Connect can not give advice to you over the internet. Your physician needs to tell you when to stop Pradaxa.

When to stop Pradaxa depends on (a) what residual blood thinning level is acceptable for a given surgery (does the drug need to be completely or only partially out of the system?), and (b) a patient’s kidney function. Both these issues are addressed in table 5 of the “Hospital Guideline” you find in this Clot Connect blog: http://clotconnect.wordpress.com/2011/04/26/pradaxa-what-your-physicianhospital-wants-to-know/ But again, you need to ask your physician when you should stop the Pradaxa.

That IS one of the issues with Pradaxa. A bleeding stroke in the brain or a bleeding injury that might normally be fixed rather easily gets to be quite the problem if the person is on Pradaxa, and when they took their dosage. With Coumadin, Vitamin K is the antidote. With Plavix, fresh frozen plasma gets enough platelets to stop the bleed. I know they are working on protocols so that ERs can handle issues. And then they need to train the ER doctors. The trouble is, even regular doctors don’t seem to have much of a clue about Pradaxa right now, so how far along are the ER doctors going to be knowledgeable?

For clarification, a few comments on reversal strategies in case of major and life threatening bleeding on various anticoagulants and anti-platelet drugs.

1. Warfarin (coumadin): What can/should be used are (a) Prothrombin Complex Concentrate (=PCC; drug names: Bebulin and Profilnine); (b) consideration of additional FFP (fresh frozen plasma; (c) vitamin K; however, vitamin K takes 24 hours or longer to reverse the warfarin effect and normalize an elevated INR; therefore, by itself it is insufficient therapy for a major bleed. (d) In case no PCC is available, recombinant factor VIIa (NovoSeven) can be considered and given.

2. Plavix is an anti-platelet drug, similar to aspirin. Plasma (FFP) is not helpful to reverse its effect. In case of major bleeding, platelet transfusions can be considered and given.

As for knowledge of ER physcians about Pradaxa: (a) Clot Connect is trying to help education by making information about blood thinners and blood clots available to health care professionals. In the case of Pradaxa and bleeding, we (a) provide the treatment guideline used at our medical instiution (University of North Carolina) – http://clotconnectmd.wordpress.com/2011/04/26/pradaxa-dabigatran-hospital-guideline, and (b) have a blog entry specifically about management of bleeding on Pradxa – http://clotconnectmd.wordpress.com/2010/12/06/pradaxa-management-of-major-bleeding. In addition: We very much encourage every patient on Pradaxa to be pro-active and to be knowledgeable about Pradaxa; this includes having some knowledge about reversal drugs and strategies. A number of blog entries for patients on Clot Connect deal with Pradaxa issues.

I would typically view a bone marrow biopsy as a “standard risk of bleeding” procedure – discussed in the management guide in the blog. Whether to stop or not stop Pradaxa – you need to discuss this with your MD.

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